Humans are to blame for wiping out honeybees: Trading colonies infected with viruses and mites ‘is creating an epidemic’

• The Deformed wing virus (DWV) is a global virus that kills off bees
• Varroa mites carrying this disease are spread due to trade of bee colonies
• While worldwide trade of European honeybees carrying infected Varroa mites has turned the pandemic into a global epidemic
• Varroa feed on larvae and virus kills off bees – a double blow to colonies

The spread of a disease that is decimating global bee populations is being largely fuelled by man.

Analysis of one of the most widespread honeybee viruses, deformed wing virus (DWV), shows that it is predominantly spread due to the trade of bee colonies.

In particular, the worldwide trade of European honeybees carrying infected Varroa mites has turned the pandemic into a global epidemic.

Analysis of one of the most widespread honeybee viruses, deformed wing virus (DWV), shows that it is predominantly spread due to the trade of bee colonies. In particular, the worldwide trade of European honeybees carrying infected Varroa mites has turned the pandemic into a global epidemic (stock image)

The study, from the University of Exeter, found that the European honeybee Apis mellifera is ‘overwhelmingly’ the source of cases of the Deformed Wing Virus infecting hives worldwide.

Although separately they are not major threats to bee populations, when the Varroa mite carries the disease, the combination is deadly, and has wiped out millions of honeybees over recent decades.
Varroa feed on bee larvae while the Deformed Wing Virus kills off bees, a devastating double blow to colonies.

The situation is adding to fears over the future of global bee populations, with major implications for biodiversity, agricultural biosecurity, global economies, and human health.
Lead author Dr Lena Wilfert, from the University of Exeter, said: ‘This is the first study to conclude that Europe is the backbone of the global spread of the bee-killing combination of Deformed Wing Virus and Varroa.

‘This demonstrates that the spread of this combination is largely man-made – if the spread was naturally occurring, we would expect to see transmission between countries that are close to each other, but we found that, for example, the New Zealand virus population originated in Europe.

‘This significantly strengthens the theory that human transportation of bees is responsible for the spread of this devastating disease.

‘We must now maintain strict limits on the movement of bees, whether they are known to carry Varroa or not.

‘It’s also really important that beekeepers at all levels take steps to control Varroa in their hives, as this viral disease can also affect wild pollinators.’

Researchers analysed sequence data of Deformed Wing Virus samples across the globe from honeybees and Varroa mites, as well as the occurrence of Varroa.

They used the information to reconstruct the spread of Deformed Wing Virus and found that the epidemic largely spread from Europe to North America, Australia and New Zealand.

The Deformed Wing Virus

Researchers analysed sequence data of Deformed Wing Virus samples across the globe from honeybees and Varroa mites, as well as the occurrence of Varroa. They used the information to reconstruct the spread of Deformed Wing Virus and found that the epidemic largely spread from Europe to North America, Australia and New Zealand. They found some two-way movement between Europe and Asia, but none between Asia and Australasia, despite their closer proximity. The team also looked at samples from other species suspected of transmitting the disease, including different species of honeybee, mite and bumblebees, but concluded that the European honeybee was the key transmitter.

Researchers analysed Deformed Wing Virus samples (pictured) across the globe from honeybees and Varroa mites, as well as the occurrence of Varroa. They used the information to reconstruct the spread of DWV and found that the epidemic largely spread from Europe to North America, Australia and New Zealand

Varroa (mite pictured) feed on bee larvae while the Deformed Wing Virus kills off bees, a devastating double blow to colonies. The situation is adding to fears over the future of global bee populations, with major implications for biodiversity, agricultural biosecurity, global economies, and human health

They found some two-way movement between Europe and Asia, but none between Asia and Australasia, despite their closer proximity.

The team also looked at samples from other species suspected of transmitting the disease, including different species of honeybee, mite and bumblebees, but concluded that the European honeybee was the key transmitter.

Professor Roger Butlin, Professor of Evolutionary Biology at the University of Sheffield, said: ‘Our study has found that the deformed wing virus is a major threat to honeybee populations across the world and this epidemic has been driven by the trade and movement of honeybee colonies.

‘Domesticated honeybee colonies are hugely important for our agriculture systems, but this study shows the risks of moving animals and plants around the world.

‘The consequences can be devastating, both for domestic animals and for wildlife. The risk of introducing viruses or other pathogens is just one of many potential dangers.’

The study, which was led by the University of Exeter and UC Berkeley and included contributions from the universities of Sheffield, Cambridge and Salford, is published in the journal Science.

1 Comment

Tom Sotiridy
on August 29, 2016 at 11:37 am

It is rare to see just one virus. They often seem to share the same circumstance needed to flourish.
Often in our area we can see deformed wing with chronic Bee paralysis parasitic mite syndrome, and others. All of these seem to be from a large mite count sometime in the last 18 months.
Nosema also seems to be around when these stress factors are in place.
Bottom line treat for mites and develop a program for long term health keeping stresses minimalized, using oils and bacteria.